Question

Two tower on top of two hills are 40 km apart .The line joining them passes 50 m above a hill halfway between the tower .What is the longest wavelength of radio wave , which can be sent between the tower without appreciable diffraction effects?

Answer 1

The longest wavelength of radio wave , which can be sent between the tower without appreciable diffraction effects is 0.125 m

1. The formula for Fresnel’s distance is given by
2. Zp = a^2/λ
3. Here Zp is Fresnel's distance , a is radius of the aperture and λ is the incident wavelength.
4. The longest wavelength of radio wave , which can be sent between the tower without appreciable diffraction effects is
5. λ = (50x50)/20000=0.125 m